Process of concentrating liquids.



P. KESTNER. PROCESS OF CONCENTRATING LIQUIDS. "APPLICATION FILED In 29, 1906.

Patented July 26, 1910;

/6 I I 5 Zia/6 awh'sce om l7 uivirnn srATns PATENT onnron.

PAUL KESTNER, F LII'LLE, FRANCE: ASSIGNO R T0 KESTNER EVAPORATOR COMPANY,

[0F PHILADELPHIA, PENNSYLVANIA; A CORPORATION OF PENNSYLVANIA.

\ rnocnss or concnnrnnrme mourns.

' Specification of Letters Patent. Patented July 26, 1910.

Application filed ma es, 1906. Serial no. 319,386.

To allwhom it may concern:

Be it known that 1, PAUL KESTNER, a citizen of the French Republic, residing at Lille, in the Nord Province of France,

have invented an Improved Process of Concentrating Liquids, of which the following is a specification.

My inventlon relates to the concentration I of liquids, and it consists of an improved method or process of evaporation wherein I am enabled to secure a high degree of'efficiency in an economical manner.-

As 1s well known 1n the practice of evaporating liquids by bringing them adjacent to or in contact with heated surfaces, better results are obtained by causing the liquid to flow in thin films or streams over sa1d surfaces. Severalattempts have been made to apply this principle in the operation of tubular evaporators, for instance, by' use of the structure shown in the British patent, of

Lillie, No. 12,391, 'dated August 28,1888.

In attempting to carry this rocess into practice, however, more or less ifliculty has eenmet with. Liqulds fiowin in a downward direction over heated sur aces tend to flow in streams and follow distinct paths or courses, anda portion of the evaporating surface is left naked or comparatively naked and is not'utilized. To remedy this defect, it has been suggested to considerably increase the volume of liquid circulated, but

as such mode of procedure involves the employment of a pump ca able of circulating a sp much larger volume 0 liquid than can be over such surface and there or also in oyment .ofcomparatively thick concentrated in a single passa evaporating volves emp layers in lieu of films, this method of evaporation has not been satisfactory, even w th the most elaborate and ingenious arrangement of nozzles or other means for distributing the liquid to'the evaporating surface or surfaces.

I method or process is based, is as follows: If,

instead of. allowing liquid simply to flow into the upper end of a vertlca tube, with or without distributing nozzles, a certain volume of steam or vapor is continuously admitted along with the liquid and admixed therewith, then said liquid will be converted into a vesicular mass and will also be, almost continuously, evenly distributed in a thin film over the whole of the interior surface of the tube and will flow with even regularity, Wetting the whole surface.

' In the accompanying sheet of drawings I have shown an evaporator or concentrating apparatus by means of which my improved method or process may be carried out, in which:

Figure l, is a vertical section of one form of complete apparatus embodying my invention; Fig. 2, is a cross-sectional vlew, taken on the line a a, Fig. 1; Fig. 3, is a cross-sectional view, taken on the hue b-b, Fig. 1, andFig. 4:, is a diagrammatic view of another form of apparatus embodying my invention.

In Fig. 1, 1 represents a casing of suitable size in which a number of vertical tubes 2 and 3 are mounted; said tubes being disposed in two groups, the tubes 2 lying adjacent the wall of the casing and incloslng the tubes 3. Plates t and 5 are mounted at the top and bottom of said casing to receive saidtubes; said plates forming the ends of the steam or heating chamber 6. The tubes pass through and extend slightly-above the upper plate 4., while their lower ends fit into the lower plate 5. Steam is introduced at 7 into the chamber 6, and the condensation therefrom runs ofi through a suitable outlet at the level of the lower plate, (not shown).

The casing is provided with a cap or cover 8, forming a chamber 9 between 1t and the upper plate 4, which chamber is common to both groups of tubes. I

The liquid to be concentrated is fed con- 'tinuously'from any suitable source to the in let 10 from which it passes lnto an annular.

chamber 11 with which the group of tubes 2, arranged adjacent the wall of the casing 1, are in communication. The liquid rises in the tubes 2 in the well known manner .of film-climbing by the action of the vapor generated within the same from said liquid by the heat, being atfirst converted into a vesicular or foamy mass, with constantly circulating andchanging bubble-walls in contactwlth the inner walls of sa1d tubes, and later beoominga .climbing film which ion overflows into the. chamber 9. From the" chamber 9, such liquid descends,

I onto a plate 15 chamber 12 upon which the.

central group of tubes and delivery ends along with he vapor formed, through the central group of tubes 3, in which it is evenlydistributed in a thin film upon the whole interior surface of each tube,"as explained above, without following courses, and passes with the attendant commixed vapor into a separating casing 1 is mounted. In lieu of this arrangement, the may be employed for the climbing body of liquid and the outer tubes for the descending body; the feeding of the respective tubes being correspondingly changed. 'The chamber 12 is provided with an eutlet 13 for the vapor.

A tubular extension 14 forms the dis-' charge outlet for the pipes 3; such exten-' sion being within the separating chamber and serving to direct the liquid and vapor having curved vanes 16 and forming a centrifugal separator whereby the liquid discharged upon the same is thrown outwardly against the sides of the separating chamber, while the attendant vapor escapes through the outlet 13. The concentrated liquid may be withdrawnfrom the 1separating chamber through the lower out- As may be seen, the process is' a combination of two stages- In the preliminary stage, a partial evaporation is obtained in the tubes 2, in which the liquid ascends. In this stage the raising of the liquid to the top of the apparatus is accomplished, and, at the same time, the volume of vapor necessary for and essential to operation of the second and main stage of the process is formed or completely filming ingto the volume of produced for the the ascending enerated. In said second stage, the liquid ows down the tubes 3 in a continuous film, and covering the surface of said tubes with the aid of the vapor formed in the liquid, and as this is the main stage of the process, the number of tubes for the ascending liquid is only limited accordvapor required to be proper carrying out of the second and main 'stageof the process. vAlthough for the sake of simplicity it is found advantageous to arrange the tubes for iquid in the same'casing as g the tubes for the descending liquid, as shown in'Fl -1, of the drawings, they may be 1n separate casings; that is to say,

evaporator for each for a preliminary or partial which 'the liquid ascends and produces the necessary volume of vapor or steam, and, a second with. tubes for the .descent of the liquid for the main stage of the process; such for instance as illustrated in Fig. 4. In this structure, A re resents a casing ,for tubes 2 in which the liquid to be concentrated ascends from an inlet 10; such casing the walls having an inlet 7 for steam to circulate around said tubesQ and effect the raising of the liquid therein; provided to remove the water of condensation from said casing. B is a casing containing tubes 3 for the downward passage of the liquid to be concentrated; the upper ends of said casin s having a communicating chamber 9 where y the liquid ascending in the tubes 2 of the casing A may pass to and overflow-the projecting ends of the tubes 8 of the casing B. The lower ends of the tubes 3 communicate with a discharge section having aplate with curved vanes to receive the liquid whereby it is thrown against of the separating chamber while the attendant vapor finds its exit through a suitable outlet; this portion of the structure being the same and operating in a manner similar to the operation of the structure shown in Fig. 1. Steam for the casing B to circulate around the tubes 3 therein, may pass directly from the steam space of the casing A, through the pipe 18, as shown, or it may be supplied from an entirely independent source.

In the described process, employing either formof apparatus shown, a regulated supply of liquldis admitted at the base of a narrow heated tube or series of tubes and enters into ebullition. The mixture of liquid and vapor, being specifically lightrises upward, the proportion of vapor steadily increasing as the mixture rises. With a proper correlation between the supply of liquid, the size of the tube or tubes and the amount of heat supplied, the liquid in the upper part "of\the tube or tubes becomes merely an annular, wall-climbing film carried forward by the onrush of a central column of vapor. As the proportion of vapor to liquid increases, so of course does the speed of travel of this current of vapor, the diameter of the tube or tubes not being increased, and, concomitantly, the power of the current to maintain the travel of the film so that the film travels with substantial uniformity throughout the height of the tube or tubes. In the lowermost extremity of the tube or tubes, the entering liquid is a solid body which becomes a vesicular mass .and finally is transformed into the described annular layer of liquid and center column of rushing vapor. Under these conditions, a maximum evaporative effect is secured since the climbin film is very thin and is uniformly distr buted over the hot walls. The

feed of liquid is, of course, so maintained that this film persists throughout the height of the tube or tubes, the feed being proportionate to the evaporation. Theliquid and vapor emerge from the'to of the tube or tu es with considerable ve ocity and in the downward ro ess through the next tube or series 0 tu es, the gravital prcgress of means (not shown) being the liquid is facilitated and made uniform by the action of the vapor. Under these conditions, the liquid does not tend to follow courses or paths, as would be normal to a layer of liquid of the same thickness flow ing under gravity alone, but istuniformly distributed over the tube walls. To produce these results, the conditions of heat and feed must of course be carefully regulated.

I claim:

1. The process of concentrating liquids, which consists in first causing a body of liquid 'to rise within a closed space under the influence of heat and of the vapor thereby generated in said liquid, and then causing said liquid together with its attendant vapor to descend within a closed space, the presence of the vapor causing the liquid to form substantially continuous thin films within said closed spaces in both ascent and vdescent whereby concentration of the same is facilitated.

2. The' process of. concentrating liquids, which consists in introducing a body of liquid at the base of a series of tubes, a pl ing heat to said tubes whereby the l1qu1d therein is vaporized andcaused to ascend in a film covering the inner surface of' said tubes, allowing said partially concentrated liquid together with its attendant vapor to pass to a second series of tubes for a downward assage, and applying heat to said latter tu es whereby the vaporization continues and the liquid is caused to cover the inner surface of said tubes in both ascent and descent thereby producing an even flow and concentration of the same.

3. The process of concentrating liquids, which consists in introducing a .body of liquid at the base of a closed space, applyin heat to said closed space whereby the liquid within the same is caused to vaporize in part and the residue to ascend therein as a climbing film, allowing saidpartially concentrated liquid to pass to a second closed space wherein it moves downward, heating said second closed space whereby the vaporization continues, the vapor developed in both spaces serving to cause the liquid to contmuously film within said second closed space to facilitate the downward flow and concentration of the same, anddischarging the concentrated liquid under such conditions as to effect separation of the same from the entrained vapor.

4. The process of concentrating 1i uids, which consists in introducing a b0( y of liquid at the base of a series of tubes, heats ing said tubes whereby the liquid is caused to partially va orize a1id-theresidue to climb in said tu es, allowing said liquid together, with its attendant vapor to pass to and descend ina series of se arate heated tubes, the vapor or steam pro uced causing an even distribution of theliquid in. continuous traveling films over substantially the whole inner surface of both sets of tubes in both ascent and descent.

, 5. The process of concentrating liquids,

which consists in circulating them in two directions in vertical passages, first in an ascending column, and second in a descending column, supplying heat to said passages whereby said li uid is caused to form vapor or steam and e ect movement of the liquid, said attendant vapor or steam serving to cause the liquid to wet and film the surfaces of both passages and induce the flow of even and substantially continuous traveling films of the liquid in both directions.

6. The process of concentrating liquids, which consists in passingthe same in ascending and descending columns out of contact vapor produced therefrom by such heat, and substantially the whole volume of vapor thus created accompanying and inducing the descending stream to film and assisting. the proper downward flow of the same.

8. The process of concentrating liquids, which consists in heating the sameto such a degree; that steam or vapor is formed, then conducting such liquid together with substantially the whole volume of its attendant vapor to a series of externally heated tubes for downward passage therein, the attendant vapor causing the li uid to film-cover the entire surface of sai tubes in both ascent and descent, thereby facilitating the downward fiow and concentration of the same, and then separating the liquid and vapor at the discharge end of said tubes.

9. The process of concentrating liquids, which consists in first lifting said liquid by heat and the vapor generated thereby in a filmiform body, and then passing said liquid. by and with its attendant vapor in a substantially continuous thin film over a heated surface whereby concentration of the same is facilitated.

In testimony whereof I have signed my name tothis specification in the presence of 

